On the trail of blood doping – a microRNA-based biomarker signature to detect autologous blood transfusions in vivo

Autologous blood doping refers to the illegal re-transfusion of any quantities of blood or blood components with blood donor and recipient being the same person. The re-transfusion of stored erythrocyte concentrates is particularly attractive to high-performance athletes as their oxygen capacity improves excessively. The identification of autologous blood doping is of utmost importance to preserve the health of competitors and to assure equality and fairness, however, there is still no reliable detection method available. Based on the biomarker potential of microRNAs in detecting the misuse of growth-promoting and erythropoiesis-stimulating drugs and their abundant expression in erythrocytes, analyzing the circulating microRNA profiles of human subjects that underwent monitored autologous blood transfusions seems to be highly promising for future detection of autologous blood doping. Therefore, 30 healthy males were randomly divided into two different treatment groups and one control group. Whole blood samples were taken at several time points at baseline, after whole blood donation and after transfusion of erythrocyte concentrates. microRNA profiles were examined by small RNA sequencing and comprehensive multivariate data analyses revealed time-specific and overall molecular signatures that are discriminative for doped and non-doped conditions with outstanding sensitivity and specificity based on receiver operating characteristics curve analyses. Further in silico analyses of the discriminative microRNA pattern substantiated the regulatory contribution of those microRNAs and the downstream target proteins AKT and TP53 in cardiovascular and hematopoietic processes. Recapped, we could establish a discriminative microRNA profile and, moreover, contribute to the understanding of physiological responses resulting from autologous blood transfusions.